(ESPAÑOL) Nine plane passengers on a domestic flight were detained and asked for ID by ICE agents. The passengers are now suing the government alleging they were subjected to an unconstitutional search.

The passengers, represented by the American Civil Liberties Union, asked a federal judge Thursday to bar the government from requiring people to produce ID before deboarding a domestic flight without a warrant or individualized reason to do so.

ACLU Deputy Legal Director Cecillia Wang said that even though passengers are required to show identification before being allowed into the area where flights are boarded, those on board the flight were “shocked” to be asked to do so before they could leave.

A Justice Department spokeswoman and a Customs and Border Protection spokesman declined to comment. The Customs and Border Protection spokesman said the lack of response “should not be construed as agreement or stipulation with any of the allegations.”

The incident occurred in February on Delta Flight 1583 from San Francisco to New York. Once on the ground at John F. Kennedy International Airport, Wang said, those on board were greeted by Customs and Border Protection agents, who stood in the boarding bridge and demanded identification documents.

Those who questioned what was happening were told it was routine, Wang said.

Authorities had been searching for an immigrant who had received a deportation order to leave the United States. The incident sparked significant controversy, as it came amid an ongoing legal fight over President Trump’s first travel ban.

An official with the Department of Homeland Security said that after the incident that the steps Customs and Border Protection agents took were normal and did not stem from a new policy or executive order.

The person whom agents had been seeking was not on the flight, authorities said.

“We basically want to stop the government from doing this again, without any individualized suspicion,” Wang said.